Tear down a dam, and a river will change. But how? And how much? To find out, Ohio Agricultural Research and Development Center scientists are looking in their own backyard.
Mazeika Sullivan and Kristin Jaeger are studying the impacts of dam removals at two former dams in Columbus: one on the Olentangy River on The Ohio State University’s Columbus campus, and another close by on the Scioto River. They’re documenting the exact changes seen in the rivers’ flow, biology and water quality.
“There’s a growing trend toward using dam removal to restore rivers, but studies documenting the rivers’ responses are limited,” said Sullivan.
“It’s logical to assume that removing a dam and restoring a river back to its natural state would provide an ecological boost,” said study sponsor John Navarro, program administrator with the Ohio Department of Natural Resources Division of Wildlife. “But until now, there have been few studies that quantify these benefits.”
- Ohio has removed 60-plus dams in the past four decades, in large part to improve water quality.
- A recent low-head dam removal project in Northeast Ohio, for example (not connected to the OARDC study), led to a previously impaired section of the Cuyahoga River meeting Ohio Environmental Protection Agency water quality standards within just six months — with fish diversity going up by 57 percent.
- Dam removal cools a river’s water — about 6 degrees Fahrenheit in a previous study in Michigan — and restores its natural temperature range.
- The improved water flow from dam removal keeps sediment from building up. Dam sediment can be full of accumulated toxins, including health threats such as polychlorinated biphenyls (PCBs).
- Sullivan and Jaeger’s research is partly funded by a grant from the National Science Foundation.
Said Navarro, “The partnership between Ohio State and the ODNR Division of Wildlife, through the Ohio Biodiversity Conservation Partnership, supports the research being conducted by Mazeika and Kris, and will provide concrete evidence of the benefits of dam removals.”